The purposes of this project are to: a) develop a series of cooperative strategies that teachers can teach to their students as they work together within cooperative group structures in mainstream classrooms; and b) develop and empirically validate the materials and procedures that are necessary for effectively and efficiently producing mastery of those strategies. The program will be field tested in mainstream elementary classrooms in public schools. A Pretest-Posttest Control Group Design will be used to evaluate the effects of instruction on students' knowledge and performance of cooperative skills before and after instruction. The goal will be to produce an instructional program that improves the cooperative performance of students with learning disabilities as well as other students in the classroom.